Cable tool underreamer



May 5, 1931. k. E. SIMPSON 1,803,873

CABLE TOOL UNDERREAMER i if Patented May '5, 1931 ROBERT E. SIMPSON, Oil TAYFT, CALIFQ GLE TGGL UNDEAMIEE a lication filed July so,

This invention relates to cable tool underreamers,

Cable tool underreamers are employed for the purpose of reaming out a well bore below b a well casing in order to make the hole of greater diameter than the Casing shoe and collars which hold the sections of the well casing together. In operation the cable tool underreamers are vertically reciprocated below the well casing removing the material from the sides of the well hole by hammerin or percussion action. The tool is subjected to very heavy strains and it is required that it be sturdy in construction, audit is also required that it be constructed so that the cutters can be readily removed for replacement or repair. It is also necessary in an underreamer of this class that the working parts be securely attached together so that there is no danger of any portion of the underreamer being lost in the well hole.

It is a general object of the present invention to provide an improved construction for a'cable tool underreamer which will be strong in construction and which has its operating parts firmly attached together and which may be readily assembled and disassembled as required.

In my prior United States Letters Patent No. 1,468,980, issued September 25, 1923, there is shown a form of underreamer in which the body of the underreamer is provided with a web extending below the body and in which the cutters of the underreamer are formed astraddle the web and provided with spaced apart upthrust receiving or bearing' faces for engagement with the bearing faces of the body. This construction of an 4 underreamer is found to be exceptionally satisfactory in operation and eliminates entirely the danger encountered with prior forms of underreamersof the underreamer plates being twisted from the body of the reamer.

An-object of the present invention is to provide an underreamer of the type illustrated in m beforeementioned patent with an improve means for attaching the cutters to the spring employed for operating the same and to provide an improved means by 1925. Serial No. 47,130.

which the cutters may be attached and detached in operation;

Various other objects and advantages of the present invention will appear from a description of the preferred form of the invention, and for this purposethere is hereinafte'r described a preferred form or ex ample of an underreamer embodying the invention, said description making reference to the accompanying drawings, in which:

Figure 1 is an elevation of the underreamer; 4

Figure 2 is an elevation at right angles to F i ure 1;

igure 3 is-an elevation mainly in vertical section on the line 33 of Figure 1;

Figure 4 is an elevation similar to Figure 1 but with the cutters in vertical section and translated to the collapsed position;

Figure 5 is a transverse section on the line 55 of Figure 1;

Figure 6 is an elevation of one of the cutters;

Figure 7 is an elevation of one of the cutters at right angles to Figure 6 and in vertical section;

Figure 8 is an elevation of one of the rod gri ping rods; and

l igure 9 is a plan view of the key of the underreamer.

Referrin to the drawings,-the under reamer is il ustrated as comprising a body that is provided at its upper end with a screw threaded socket 16 and with a wrenchfiat 17 about midway along the body. The body 15 is illustrated as provided at its upper end with a hollow bore forming a spring chamber 19. The sprin chamber 19 opens at its top into the three ed socket 16 and extends downwardly lengthwise of the body 15 and communicates as indicated at 20 with guideways 21 and 22. The lower end of the body 15 is indicated as terminating in a cutter holding tongue or web 23. The web 23 is illustrated as having its outer edges provided at their sides with cutter retaining ribs 24 and 25 which cutter retaining ribs are indicated as preferably enlarged upwardly in a direction arallel with the plane of the web 23 there y forming between the ribs 24;

and an upwardly reduced recess 26 in the face of the web 23. Below the ribs 24 and 25, the sides of the web 23 converge as indicated at 66'. The web 23 is also provided in its center with a stop 27 which is preferably removable and serves the purpose of preventing the cutters of the reamer from dropping ofl the reamer. "In its preferred form, the stop 27' is indicated in the form of a pin 27, the pin 27 being threaded into an opening) 68 in the web 23. Above the web 23 and at 0th sides of the web 23 the body provides horizontal flat faces 28 and 29 which faces operate as hearing faces receiving upthrust from the cutters of the reamer when the same is reciprocated in operation.

The underreamer is illustrated as provided with two cutters 30 and 31 which are preferably of similar construction and the cutters are designed to be mounted astride opposite sides of the web 23. Inasmuch as the cutters are of duplicate construction, only one of the cutters will be specifically described. The cutter 30, for example, is indicated as provided at its upper end with two horizontally alined faces 32 and 33 which are intended for engagement with the upthrust bearing faces 28 and 29 of the body 15. These upthrust bearing faces upon the cutter 30 are spaced as widely apart as the size of the underreamer will permit-so as to assist in preventing the cutter 30 from being twisted in operation. The cutter 30 is furtherindicated as provided with an undercut way 34 which permits the cutter 30 to be slid over. the ribs 24"on the web 23 of the body. The base 35 of the undercut way is indicated as tapered inwardly so that the base of the Way 34 may form a riding sun face adaptedfor translating the cutter to an expanded or reaming position when the cutter is forced upwardly over the rib 24 into the position illustrated in Figure 1. The

' upper portion of said ridingsurface 35 isindicated as cut away at 36 in order to permit the cutter 30 when it is translated to the lower (position indicated-in Figure 4 to swing inwar ly to a collapsed position.

At the top of the rider Surface 35, the cutter 30 is indicated as forming ashoulder 37 which, in the expanded position of the cutter 30, is adapted to catch upon the shoe of a well casing through which the underreamer is operating and force the cutters 30 into the collapsed position whenever the underreamer is drawn upwardly through the easing by the shoe. The lower end of the cutter 30 terminates in a broad face 38 which is the cutting or crushing face of the cutter and the inner face. 39 of the cutter tapers outwardly when the cutter is in the expanded position so as to provide first, a space between the cutters in the reaming position for the passage of the detritus formed, and second, to permit the cutting faces 38 of the cutter to swing together when it is desired to translate the cutters to the non-reaming or collapsed position. The cutter 30 is also indicated as provided on its'inner face '39 at each side of the undercut way 34 with gripper head holding recesses 40 and with recesses 41 of less depth thereabove extending to the top of the cutters.

The gripper head holding recesses 40 are engaged by the heads 42 of cutter gripping rods 43. The cutter gripping rods 43 are, in turn, indicated as slidably mounted within the ways 21 and 22 formed in the body 15. The underreamer is illustrated as preferably provided with two of the cutter gripping rods 43, one extending each side of the web 23 of the body. As best illustrated in Figure 8, the rods 43 are provided with reduced necks 44 near their lower ends and terminate in the heads 42 which extend at both sides of the necks 44. The rods 43 are thus adapted to have their heads 42 engage in recesses 40 of both of the opposed cutters 30 and 31 so that each of the cutters 30 and 31 is engaged by two of the cutter gripping rods. The upper ends of the cutter gripping rods 43 are indicated as provided with Vertical openings or key slots 45. a

The key slots 45 of the cutter gripping rods 43 are indicated as receiving a key 46 which works in the body 15 of the reamer in a narrow key-way slot 47 which extends completely through the underreamer body 15. The key 46, as best illustrated in Figure 9, is formed at its opposite edges with complementary notches or recesses 48 and said recesses 48 are. of a width designed to fit the head 49 of a cutter actuating rod 50.

The cutter actuating rod 50 is indicated as mounted mainly within the spring chamber 19 of the body 15 and is provided at its upper endwith a head 51 held to the rod 50 by a nut 52 or other suitable means. The head 51 is indicated as engaging the top end of a compression spring 53 coiled around the rod 50 and engaging at its lower end a spring seat 54'at the bottom of the spring chamber 19. The head 49 of the actuating rod 50 is provided with a narrow key slot 55 for receiving the key 46. In operation the force of the spring 53 holds the head 49 of the operating rod 50 firmly within one of the notches 48 in the key thereby insuring that the key 48 cannot become dislodged from the underreamer. The purpose of two complementary notches 48 inthe key 46 is to guard against the accidental insertion of the key 46 in the apparatus in the wrong manner. If one of the edges of the key 46 were made plain and this edge placed at the bottom in operation. the key 46 would become dislodged from the underreamer and the underreamer would then be dependent upon the stop 27 for holding the cutters to the body.

eoaeve To the top of the body 15 there is indicated attached a sub 60 which provides a means for attaching the undcrreanier to the operating string. The underreamer body 15 is also indicated as provided wit-l1 one or more sets of alined openings 61 slightly below the top of the nut 52. Said openings serve as a means which will permit the insertion of a pin over the nut 52 of the actuating rod when the spring is in the compressed position and thus lock the spring in the compressed position.

The operation of assembling and disassembling the iinderreamer is as follows: The sub 60 is first removed and the spring and actuating rod 50 are placed in the spring chamber 19. The spring is then compressed and a pin inserted in one of the pairs of openings 61 to hold the spring in the con'lpresscd position.- The cutters 30 and 31 are then placed upon the lower end of the web 23 and the cut t-er gripping rods 43 are attached to the cutters and pushed upwardly into the ways 21 and 22 until the openings 45 in said rods aline with the opening in the actuating rod. The key 16 is then inserted in the key- \vay 47 into said alined openings. The pin in the opening is then removed, releasing the spring 53 which immediately draws up the actuating rod 50 against the key 16 and all of the parts are held in operating position. As a final operation, the stop 27 is placed in its opening in the web 23. \Vhen it is desired to disassemble the underreamer. the cutters 3O ahd 31 are first pulled downwardly to compress the spring 53. The pin is then reinserted in the openings 61 and the cutters ma be released thus releasin the force on the key 46. The key46 is then wedged out from the openings in the rods 43 and 50 after which, by removal of the stop 27, the cutters and cutter gripping rods may be removed.

The form of underreamer herein described maintains the spring in a substantially closed chamber and the body of the underreamer contains but a narrow opening therein which facilitates keeping detritus out of the working parts of the underreamer.

No claim is made to any particular shape of the two flats 17, nor to their position rela tive to the hole 61'and to any novelty in the spring retaining washer 51, or to the use of bolt and not, as distinguished from any other form of stop for the cutters, and no claim is made to the details of the. shape of parts 14 and 43, except as embodied in the accompanying claims. No claim is made in this application to the bevels on corners of the key 46.

While the particular form of the invention herein described is well adapted to carry out the objects of the invention, it is to be understood that various modifications and changes may be made without departing from the in- 65 vention, and the invention includes all such modifications and changes as come within the scope of the following appendedclaims.

I claim:

1. An underreamer comprising a body,

reaming cutters mounted by the body and vertically movable from a contracted position to an expanded position, a cutter oper ating rod within the body, a spring connected to said rod, a cutter gripping rod at one end engaging both of said cutters and extending into said body, said rod being mounted to move on its axis, and means within the body for attaching said gripping rod to said to said rod, a cutter gripping rod engaging said cutters at one end and extending into saidbody, said rod being mounted to move on its axis, and a key engaging said gripping rod and operating rod for attaching the same together.

3. An underreamer comprising a body, reaming cutters mounted by the hodyand vertically movable from a contracted position'to an expanded position, a cutter-operating rod withinv the body, a spring connected to said rod, a cutter gripping rod engaging said cutters at one end and extending into said body, and a key engaging said gripping rod and operating rod for attaching the same to gether, said key having complementary rod engaging notches at its opposite sides.

4. An underreamer comprising a body, reaming cutters mounted by the body and vertically movable from a collapsed toa.

reaming position, said body having a spring chamber, a spring within said chamber, an operating rod connected with said spring, the body further having gripper rod holding ways, gripper rods vertically'movable on their axis in said Ways and engaging said cutters at their lower ends, the body having a lateral key admitting passage, and a key movable through said passage and engaging the gripper rods and operating rod for attaching the same together.

5. An underreamer comprising a body, reaming cutters mounted by the body and vertically movable from a contracted position to an expanded position, a cutter operating rod within the body, a spring con-' nected to said-rod, a gripper rod engaging said cutters at one end and extending into said body, said body being provided with guide-ways for guiding the gripper rods to move in a vertical direction, and a key within the body for attaching said gripper rod to said operating rod, the body being provided with a lateral opening adjacent said key through which said key may be inserted.

6. An underreamer comprising a body,

tion to an expanded position, a cutter oper-- reaming cutters mounted bypthe body and vertically movable from a contracted posiating rod within the body, a spring connected to said rod, a cutter gripping rod engaging said cutter at one end and extending into said body, and means within the body for attaching said gripping rod to said operating rod, the body being provided with means at the upper end of the spring for holding the spring in a compressed position during the operations of assembling and disassembling the underreamer.

7. An underreamer comprising a body, reaming cutters mounted by the body and vertically movable from a contracted position to an expanded position, a cutter operating rod within the body, a spring connected to said rod, a cutter gripping rod engaging said cutters at one end and extending into said body, said gripper rod being movable on its axis, and a key engaging said gripping rod and operating rod for attaching the same together, the body being provided with means at the upper end of the spring for holding the spring in a compressed position during the operations of assembling and disassembling the underreamer." I

8. An underreamer comprising a body,

reaming cutters mounted by the body and vertically movable from a contracted position to an expanded position, a cutter operating rod within the body, a spring connected to said rod, a cutter gripping rod engaging said cutters at one end and extending 1nto said body, and a key engaging said gripping rod and operating rod for attaching the same together, said key'having complementary rod engaging notches at its opposite sides, the body being provided with means at the upper end of the spring for holding the spring in a compressed position during the operations of assembling and disassembling the underreamer.

' 9. An underreamer comprising av body, reaming cutters mounted b the body and vertically movable from a col apsed to a reaming position, said body having a spring chamber, a spring within said chamber, an operating rod connected with said spring, the body further having gripper rod holding ways, gripper rods vertically movable in said ways and engaging said cutters at their lower ends, the body having a lateral key admitting passage, and a key movable through said passage and engaging the gripper rods and operating rod for attaching the same together, the body being provided with means at the upper end of the spring for holding the spring in a compressed position durin the operations of assembling and 'disassem ling the underreamer.

10(An underreamer comprising a body,

reaming cutters mounted by thebody and vertically movable from a contracted position to an expanded position, a cutter operating rod within the body, a spring connected -to said rod, a gripper rod engaging said cutters at one end and extending'into said body, said body being provided with guide-Ways ,for

guiding the gripper rods to move in a vertical 7 direction, and a key within the body for attaching said gripper rod to said operating rod, the body being provided with .a lateral opening adjacent said key through which said key may be inserted, the body being provided with means at the upper end of the spring for p lapsed position to a reaming position, a cutter operating rod within the body, a spring connected to'said rod, a gripper rod engaging said cutters at one end and extending into said body to said operating rod, said gripper rod being movable "on its axis, and a key for attaching said gripper rod to said operating rod.

12. An underreamer comprising a body terminating in a web, a pair of reaming cutters mounted astride said web and vertically movable from a collapsed position to a reaming position, a cutter operating rod within the body, spring means connected to said rod, gripper rods having heads, there being a gripper rod with a head disposed at each side of said web andeach head engaging each of the cutters, the gripper rods extending into the body to said operating rod, guided to move on its axis anda key for attaching said gripper rods to said operating rod.

13. An underreamer comprising a body terminating in a web, a reaming cutter mounted astride each edge of said web, the cutters being movable upwardly to a reaming position and downwardly to a collapsed position, a gripper rod extending each side of said web, said gripper rods each having heads for engaging both of said cutters, the gripper rods extending into said body, a spring controlled pperating rod within said body, and a key for attaching said operating rod to said gripper rods, said key having a notch on each of its sides, said notches being adapted tofit said operating rod.

In witness that I claim the foregoing, I have hereunto set my hand this 26th day of June,

RQBERT E. SIMPSON. 

